Chimpanzee seed dispersal in a montane forest fragment in Rwanda.

Unlabelled: Primate seed dispersal plays an important role in forest regeneration. It may be particularly important to anthropogenically disturbed habitats such as forest fragments. However, few studies have examined primate seed dispersal in these types of environments.

Correlations between social context and fecal glucocorticoid metabolite concentrations in free-ranging female gray-cheeked mangabeys (Lophocebus albigena) in Kibale National Park, Uganda.

An elevated concentration of glucocorticoids is an indicator of stress, and chronically high glucocorticoid levels are often associated with poor health and reduced fertility. We explored conditions that might be stressors in the lives of adult female gray-cheeked mangabeys (Lophocebus albigena) by measuring fecal glucocorticoid metabolites (fGCM) concentrations. During a six-month study we collected 109 fecal samples from 28 adult females from five groups in Kibale National Park, Uganda.

Eastern chimpanzees, but not bonobos, represent a simian immunodeficiency virus reservoir.

Chimpanzees in west central Africa (Pan troglodytes troglodytes) are endemically infected with simian immunodeficiency viruses (SIVcpzPtt) that have crossed the species barrier to humans and gorillas on at least five occasions, generating pandemic and nonpandemic forms of human immunodeficiency virus type 1 (HIV-1) as well as gorilla SIV (SIVgor). Chimpanzees in east Africa (Pan troglodytes schweinfurthii) are also infected with SIVcpz; however, their viruses (SIVcpzPts) have never been found in humans. To examine whether this is due to a paucity of natural infections, we used noninvasive methods to screen wild-living eastern chimpanzees in the Democratic Republic of the Congo (DRC), Uganda, and Rwanda.

Long-term Site Fidelity and Individual Home Range Shifts in Lophocebus albigena.

We investigated long-term site fidelity of gray-cheeked mangabey (Lophocebus albigena) groups in Kibale National Park, Uganda. Concurrently, we monitored shifts in home range by individual females and subadult and adult males. We documented home range stability by calculating the area of overlap in successive years, and by recording the drift of each group's monthly centroid from its initial location.

Food site residence time and female competitive relationships in wild gray-cheeked mangabeys (Lophocebus albigena).

Authors of socioecological models propose that food distribution affects female social relationships in that clumped food resources, such as fruit, result in strong dominance hierarchies and favor coalition formation with female relatives. A number of Old World monkey species have been used to test predictions of the socioecological models. However, arboreal forest-living Old World monkeys have been understudied in this regard, and it is legitimate to ask whether predominantly arboreal primates living in tropical forests exhibit similar or different patterns of behavior.

Demography and Life Histories of Sympatric Patas Monkeys, Erythrocebus patas, and Vervets, Cercopithecus aethiops, in Laikipia, Kenya.

Mortality patterns are thought to be strong selective forces on life history traits, with high adult mortality and low immature mortality favoring early and rapid reproduction. Patas monkeys (Erythrocebus patas) have the highest potential rates of population increase for their body size of any haplorhine primate because they reproduce both earlier and more often. We report here 10 yr of comparative demographic data on a population of patas monkeys and a sympatric population of vervet monkeys (Cercopithecus aethiops), a closely related species differing in aspects of social system, ecology, and life history.